/**
 * @license
 * Copyright (c) 2013, Brandon Jones, Colin MacKenzie IV. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

import { GLMAT_RANDOM, GLMAT_ARRAY_TYPE } from './common';

/**
 * @class 3 Dimensional Vector
 * @name vec3
 */

var vec3 = {};

/**
 * Creates a new, empty vec3
 *
 * @returns {vec3} a new 3D vector
 */
vec3.create = function() {
    var out = new GLMAT_ARRAY_TYPE(3);
    out[0] = 0;
    out[1] = 0;
    out[2] = 0;
    return out;
};

/**
 * Creates a new vec3 initialized with values from an existing vector
 *
 * @param {vec3} a vector to clone
 * @returns {vec3} a new 3D vector
 */
vec3.clone = function(a) {
    var out = new GLMAT_ARRAY_TYPE(3);
    out[0] = a[0];
    out[1] = a[1];
    out[2] = a[2];
    return out;
};

/**
 * Creates a new vec3 initialized with the given values
 *
 * @param {Number} x X component
 * @param {Number} y Y component
 * @param {Number} z Z component
 * @returns {vec3} a new 3D vector
 */
vec3.fromValues = function(x, y, z) {
    var out = new GLMAT_ARRAY_TYPE(3);
    out[0] = x;
    out[1] = y;
    out[2] = z;
    return out;
};

/**
 * Copy the values from one vec3 to another
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the source vector
 * @returns {vec3} out
 */
vec3.copy = function(out, a) {
    out[0] = a[0];
    out[1] = a[1];
    out[2] = a[2];
    return out;
};

/**
 * Set the components of a vec3 to the given values
 *
 * @param {vec3} out the receiving vector
 * @param {Number} x X component
 * @param {Number} y Y component
 * @param {Number} z Z component
 * @returns {vec3} out
 */
vec3.set = function(out, x, y, z) {
    out[0] = x;
    out[1] = y;
    out[2] = z;
    return out;
};

/**
 * Adds two vec3's
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {vec3} out
 */
vec3.add = function(out, a, b) {
    out[0] = a[0] + b[0];
    out[1] = a[1] + b[1];
    out[2] = a[2] + b[2];
    return out;
};

/**
 * Subtracts vector b from vector a
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {vec3} out
 */
vec3.subtract = function(out, a, b) {
    out[0] = a[0] - b[0];
    out[1] = a[1] - b[1];
    out[2] = a[2] - b[2];
    return out;
};

/**
 * Alias for {@link vec3.subtract}
 * @function
 */
vec3.sub = vec3.subtract;

/**
 * Multiplies two vec3's
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {vec3} out
 */
vec3.multiply = function(out, a, b) {
    out[0] = a[0] * b[0];
    out[1] = a[1] * b[1];
    out[2] = a[2] * b[2];
    return out;
};

/**
 * Alias for {@link vec3.multiply}
 * @function
 */
vec3.mul = vec3.multiply;

/**
 * Divides two vec3's
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {vec3} out
 */
vec3.divide = function(out, a, b) {
    out[0] = a[0] / b[0];
    out[1] = a[1] / b[1];
    out[2] = a[2] / b[2];
    return out;
};

/**
 * Alias for {@link vec3.divide}
 * @function
 */
vec3.div = vec3.divide;

/**
 * Returns the minimum of two vec3's
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {vec3} out
 */
vec3.min = function(out, a, b) {
    out[0] = Math.min(a[0], b[0]);
    out[1] = Math.min(a[1], b[1]);
    out[2] = Math.min(a[2], b[2]);
    return out;
};

/**
 * Returns the maximum of two vec3's
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {vec3} out
 */
vec3.max = function(out, a, b) {
    out[0] = Math.max(a[0], b[0]);
    out[1] = Math.max(a[1], b[1]);
    out[2] = Math.max(a[2], b[2]);
    return out;
};

/**
 * Scales a vec3 by a scalar number
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the vector to scale
 * @param {Number} b amount to scale the vector by
 * @returns {vec3} out
 */
vec3.scale = function(out, a, b) {
    out[0] = a[0] * b;
    out[1] = a[1] * b;
    out[2] = a[2] * b;
    return out;
};

/**
 * Adds two vec3's after scaling the second operand by a scalar value
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @param {Number} scale the amount to scale b by before adding
 * @returns {vec3} out
 */
vec3.scaleAndAdd = function(out, a, b, scale) {
    out[0] = a[0] + (b[0] * scale);
    out[1] = a[1] + (b[1] * scale);
    out[2] = a[2] + (b[2] * scale);
    return out;
};

/**
 * Calculates the euclidian distance between two vec3's
 *
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {Number} distance between a and b
 */
vec3.distance = function(a, b) {
    var x = b[0] - a[0],
        y = b[1] - a[1],
        z = b[2] - a[2];
    return Math.sqrt(x*x + y*y + z*z);
};

/**
 * Alias for {@link vec3.distance}
 * @function
 */
vec3.dist = vec3.distance;

/**
 * Calculates the squared euclidian distance between two vec3's
 *
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {Number} squared distance between a and b
 */
vec3.squaredDistance = function(a, b) {
    var x = b[0] - a[0],
        y = b[1] - a[1],
        z = b[2] - a[2];
    return x*x + y*y + z*z;
};

/**
 * Alias for {@link vec3.squaredDistance}
 * @function
 */
vec3.sqrDist = vec3.squaredDistance;

/**
 * Calculates the length of a vec3
 *
 * @param {vec3} a vector to calculate length of
 * @returns {Number} length of a
 */
vec3.length = function (a) {
    var x = a[0],
        y = a[1],
        z = a[2];
    return Math.sqrt(x*x + y*y + z*z);
};

/**
 * Alias for {@link vec3.length}
 * @function
 */
vec3.len = vec3.length;

/**
 * Calculates the squared length of a vec3
 *
 * @param {vec3} a vector to calculate squared length of
 * @returns {Number} squared length of a
 */
vec3.squaredLength = function (a) {
    var x = a[0],
        y = a[1],
        z = a[2];
    return x*x + y*y + z*z;
};

/**
 * Alias for {@link vec3.squaredLength}
 * @function
 */
vec3.sqrLen = vec3.squaredLength;

/**
 * Negates the components of a vec3
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a vector to negate
 * @returns {vec3} out
 */
vec3.negate = function(out, a) {
    out[0] = -a[0];
    out[1] = -a[1];
    out[2] = -a[2];
    return out;
};

/**
 * Returns the inverse of the components of a vec3
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a vector to invert
 * @returns {vec3} out
 */
vec3.inverse = function(out, a) {
  out[0] = 1.0 / a[0];
  out[1] = 1.0 / a[1];
  out[2] = 1.0 / a[2];
  return out;
};

/**
 * Normalize a vec3
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a vector to normalize
 * @returns {vec3} out
 */
vec3.normalize = function(out, a) {
    var x = a[0],
        y = a[1],
        z = a[2];
    var len = x*x + y*y + z*z;
    if (len > 0) {
        //TODO: evaluate use of glm_invsqrt here?
        len = 1 / Math.sqrt(len);
        out[0] = a[0] * len;
        out[1] = a[1] * len;
        out[2] = a[2] * len;
    }
    return out;
};

/**
 * Calculates the dot product of two vec3's
 *
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {Number} dot product of a and b
 */
vec3.dot = function (a, b) {
    return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
};

/**
 * Computes the cross product of two vec3's
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @returns {vec3} out
 */
vec3.cross = function(out, a, b) {
    var ax = a[0], ay = a[1], az = a[2],
        bx = b[0], by = b[1], bz = b[2];

    out[0] = ay * bz - az * by;
    out[1] = az * bx - ax * bz;
    out[2] = ax * by - ay * bx;
    return out;
};

/**
 * Performs a linear interpolation between two vec3's
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the first operand
 * @param {vec3} b the second operand
 * @param {Number} t interpolation amount between the two inputs
 * @returns {vec3} out
 */
vec3.lerp = function (out, a, b, t) {
    var ax = a[0],
        ay = a[1],
        az = a[2];
    out[0] = ax + t * (b[0] - ax);
    out[1] = ay + t * (b[1] - ay);
    out[2] = az + t * (b[2] - az);
    return out;
};

/**
 * Generates a random vector with the given scale
 *
 * @param {vec3} out the receiving vector
 * @param {Number} [scale] Length of the resulting vector. If ommitted, a unit vector will be returned
 * @returns {vec3} out
 */
vec3.random = function (out, scale) {
    scale = scale || 1.0;

    var r = GLMAT_RANDOM() * 2.0 * Math.PI;
    var z = (GLMAT_RANDOM() * 2.0) - 1.0;
    var zScale = Math.sqrt(1.0-z*z) * scale;

    out[0] = Math.cos(r) * zScale;
    out[1] = Math.sin(r) * zScale;
    out[2] = z * scale;
    return out;
};

/**
 * Transforms the vec3 with a mat4.
 * 4th vector component is implicitly '1'
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the vector to transform
 * @param {mat4} m matrix to transform with
 * @returns {vec3} out
 */
vec3.transformMat4 = function(out, a, m) {
    var x = a[0], y = a[1], z = a[2],
        w = m[3] * x + m[7] * y + m[11] * z + m[15];
    w = w || 1.0;
    out[0] = (m[0] * x + m[4] * y + m[8] * z + m[12]) / w;
    out[1] = (m[1] * x + m[5] * y + m[9] * z + m[13]) / w;
    out[2] = (m[2] * x + m[6] * y + m[10] * z + m[14]) / w;
    return out;
};

/**
 * Transforms the vec3 with a mat3.
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the vector to transform
 * @param {mat4} m the 3x3 matrix to transform with
 * @returns {vec3} out
 */
vec3.transformMat3 = function(out, a, m) {
    var x = a[0], y = a[1], z = a[2];
    out[0] = x * m[0] + y * m[3] + z * m[6];
    out[1] = x * m[1] + y * m[4] + z * m[7];
    out[2] = x * m[2] + y * m[5] + z * m[8];
    return out;
};

/**
 * Transforms the vec3 with a quat
 *
 * @param {vec3} out the receiving vector
 * @param {vec3} a the vector to transform
 * @param {quat} q quaternion to transform with
 * @returns {vec3} out
 */
vec3.transformQuat = function(out, a, q) {
    // benchmarks: http://jsperf.com/quaternion-transform-vec3-implementations

    var x = a[0], y = a[1], z = a[2],
        qx = q[0], qy = q[1], qz = q[2], qw = q[3],

        // calculate quat * vec
        ix = qw * x + qy * z - qz * y,
        iy = qw * y + qz * x - qx * z,
        iz = qw * z + qx * y - qy * x,
        iw = -qx * x - qy * y - qz * z;

    // calculate result * inverse quat
    out[0] = ix * qw + iw * -qx + iy * -qz - iz * -qy;
    out[1] = iy * qw + iw * -qy + iz * -qx - ix * -qz;
    out[2] = iz * qw + iw * -qz + ix * -qy - iy * -qx;
    return out;
};

/**
 * Rotate a 3D vector around the x-axis
 * @param {vec3} out The receiving vec3
 * @param {vec3} a The vec3 point to rotate
 * @param {vec3} b The origin of the rotation
 * @param {Number} c The angle of rotation
 * @returns {vec3} out
 */
vec3.rotateX = function(out, a, b, c){
   var p = [], r=[];
      //Translate point to the origin
      p[0] = a[0] - b[0];
      p[1] = a[1] - b[1];
    p[2] = a[2] - b[2];

      //perform rotation
      r[0] = p[0];
      r[1] = p[1]*Math.cos(c) - p[2]*Math.sin(c);
      r[2] = p[1]*Math.sin(c) + p[2]*Math.cos(c);

      //translate to correct position
      out[0] = r[0] + b[0];
      out[1] = r[1] + b[1];
      out[2] = r[2] + b[2];

    return out;
};

/**
 * Rotate a 3D vector around the y-axis
 * @param {vec3} out The receiving vec3
 * @param {vec3} a The vec3 point to rotate
 * @param {vec3} b The origin of the rotation
 * @param {Number} c The angle of rotation
 * @returns {vec3} out
 */
vec3.rotateY = function(out, a, b, c){
    var p = [], r=[];
    //Translate point to the origin
    p[0] = a[0] - b[0];
    p[1] = a[1] - b[1];
    p[2] = a[2] - b[2];

    //perform rotation
    r[0] = p[2]*Math.sin(c) + p[0]*Math.cos(c);
    r[1] = p[1];
    r[2] = p[2]*Math.cos(c) - p[0]*Math.sin(c);

    //translate to correct position
    out[0] = r[0] + b[0];
    out[1] = r[1] + b[1];
    out[2] = r[2] + b[2];

    return out;
};

/**
 * Rotate a 3D vector around the z-axis
 * @param {vec3} out The receiving vec3
 * @param {vec3} a The vec3 point to rotate
 * @param {vec3} b The origin of the rotation
 * @param {Number} c The angle of rotation
 * @returns {vec3} out
 */
vec3.rotateZ = function(out, a, b, c){
    var p = [], r=[];
    //Translate point to the origin
    p[0] = a[0] - b[0];
    p[1] = a[1] - b[1];
    p[2] = a[2] - b[2];

    //perform rotation
    r[0] = p[0]*Math.cos(c) - p[1]*Math.sin(c);
    r[1] = p[0]*Math.sin(c) + p[1]*Math.cos(c);
    r[2] = p[2];

    //translate to correct position
    out[0] = r[0] + b[0];
    out[1] = r[1] + b[1];
    out[2] = r[2] + b[2];

    return out;
};

/**
 * Perform some operation over an array of vec3s.
 *
 * @param {Array} a the array of vectors to iterate over
 * @param {Number} stride Number of elements between the start of each vec3. If 0 assumes tightly packed
 * @param {Number} offset Number of elements to skip at the beginning of the array
 * @param {Number} count Number of vec3s to iterate over. If 0 iterates over entire array
 * @param {Function} fn Function to call for each vector in the array
 * @param {Object} [arg] additional argument to pass to fn
 * @returns {Array} a
 * @function
 */
vec3.forEach = (function() {
    var vec = vec3.create();

    return function(a, stride, offset, count, fn, arg) {
        var i, l;
        if(!stride) {
            stride = 3;
        }

        if(!offset) {
            offset = 0;
        }

        if(count) {
            l = Math.min((count * stride) + offset, a.length);
        } else {
            l = a.length;
        }

        for(i = offset; i < l; i += stride) {
            vec[0] = a[i]; vec[1] = a[i+1]; vec[2] = a[i+2];
            fn(vec, vec, arg);
            a[i] = vec[0]; a[i+1] = vec[1]; a[i+2] = vec[2];
        }

        return a;
    };
})();

/**
 * Get the angle between two 3D vectors
 * @param {vec3} a The first operand
 * @param {vec3} b The second operand
 * @returns {Number} The angle in radians
 */
vec3.angle = function(a, b) {

    var tempA = vec3.fromValues(a[0], a[1], a[2]);
    var tempB = vec3.fromValues(b[0], b[1], b[2]);

    vec3.normalize(tempA, tempA);
    vec3.normalize(tempB, tempB);

    var cosine = vec3.dot(tempA, tempB);

    if(cosine > 1.0){
        return 0;
    } else {
        return Math.acos(cosine);
    }
};

export default vec3;
